Characteristics of phantom limb pain in U.S. civilians and service members.

OBJECTIVES: The population of Americans with limb loss is on the rise, with a different profile than in previous generations (e.g., greater incidence of amputation due to diabetes). This study aimed to identify the key characteristics of phantom limb sensation (PLS) and pain (PLP) in a current sample of Americans with limb loss. METHODS: This cross-sectional study is the first large-scale (n=649) study on PLP in the current population of Americans with limb loss. A convenience sample of military and civilian persons missing one or more major limbs was surveyed regarding their health history and experience with phantom limb phenomena. RESULTS: Of the participants surveyed, 87% experienced PLS and 82% experienced PLP. PLS and PLP typically first occurred immediately after amputation (47% of cases), but for a small percentage (3-4%) onset did not occur until over a year after amputation. Recent PLP severity decreased over time (ß=0.028, 95% CI: -0.05-0.11), but most participants reported PLP even 10 years after amputation. Higher levels of recent PLP were associated with telescoping (ß=0.123, 95% CI: 0.04-0.21) and higher levels of pre-amputation pain (ß=0.104, 95% CI: 0.03-0.18). Those with congenitally missing limbs experienced lower levels of recent PLP (t (37.93)=3.93, p<0.01) but there were no consistent differences in PLP between other amputation etiologies. CONCLUSIONS: Phantom limb phenomena are common and enduring. Telescoping and pre-amputation pain are associated with higher PLP. Persons with congenitally missing limbs experience lower levels of PLP than those with amputation(s), yet PLP is common even in this subpopulation.

Percutaneous Peripheral Nerve Stimulation to Control Postoperative Pain, Decrease Opioid Use, and Accelerate Functional Recovery Following Orthopedic Trauma.

Orthopedic trauma is a significant military problem, causing several of the most disabling conditions with high rates of separation from duty and erosion of military readiness. The objective of this report is to summarize the findings of case series of a non-opioid therapy-percutaneous peripheral nerve stimulation (PNS) - and describe its potential for postoperative analgesia, early opioid cessation, and improved function following orthopedic trauma. Percutaneous PNS has been evaluated for the treatment of multiple types of pain, including two case series on postoperative pain following total knee replacement (n = 10 and 8, respectively) and a case series on postamputation pain (n = 9). The orthopedic trauma induced during TKR is highly representative of multiple types of orthopedic trauma sustained by Service members and frequently produces intense, prolonged postoperative pain and extended opioid use following surgery. Collectively, the results of these three clinical studies demonstrated that percutaneous PNS can provide substantial pain relief, reduce opioid use, and improve function. These outcomes suggest that there is substantial potential for the use of percutaneous PNS following orthopedic trauma.

Evaluation of the Validity and Response Burden of Patient Self-Report Measures of the Pain Assessment Screening Tool and Outcomes Registry (PASTOR).

BACKGROUND: In 2009, the Army Pain Management Task Force was chartered. On the basis of their findings, the Department of Defense recommended a comprehensive pain management strategy that included development of a standardized pain assessment system that would collect patient-reported outcomes data to inform the patient-provider clinical encounter. The result was the Pain Assessment Screening Tool and Outcomes Registry (PASTOR). The purpose of this study was to assess the validity and response burden of the patient-reported outcome measures in PASTOR. METHODS: Data for analyses were collected from 681 individuals who completed PASTOR at baseline and follow-up as part of their routine clinical care. The survey tool included self-report measures of pain severity and pain interference (measured using the National Institutes of Health Patient-Reported Outcome Measurement Information System [PROMIS] and the Defense and Veterans Pain Rating scale). PROMIS measures of pain correlates also were administered. Validation analyses included estimation of score associations among measures, comparison of scores of known groups, responsiveness, ceiling and floor effects, and response burden. RESULTS: Results of psychometric testing provided substantial evidence for the validity of PASTOR self-report measures in this population. Expected associations among scores largely supported the concurrent validity of the measures. Scores effectively distinguished among respondents on the basis of their self-reported impressions of general health. PROMIS measures were administered using computer adaptive testing and each, on average, required less than 1 minute to administer. Statistical and graphical analyses demonstrated the responsiveness of PASTOR measures over time.

Stellate Ganglion Block for the Treatment of Posttraumatic Stress Disorder: A Randomized, Double-Blind, Controlled Trial.

OBJECTIVE: In this study, we aimed to determine if stellate ganglion block (SGB) could reduce symptoms of posttraumatic stress disorder (PTSD) in comparison with sham therapy in military service members. METHODS: In a randomized trial in which both participants and assessors were blind, participants with PTSD received either an SGB or a sham procedure. Posttraumatic stress disorder symptoms were measured using the CAPS (Clinician-Administered PTSD Scale) and self-report measures of PTSD, depression, anxiety, and pain. Subjects underwent assessment before the procedure and at 1 week, 1 month, and 3 months after the procedure. Patients receiving sham injections were allowed to cross over to the treatment group, and participants who maintained criteria for PTSD were allowed to receive a second SGB treatment. RESULTS: Posttraumatic stress disorder, anxiety, and depression scores all showed improvement across time, but there was no statistically or clinically relevant difference in outcomes between the active and control groups. Individuals who crossed over from sham treatment to SGB similarly showed no greater improvement with the SGB treatment. Improvement in CAPS was greater with a second SGB treatment than after the first treatment. CONCLUSIONS: Although previous case series have suggested that SGB offers an effective intervention for PTSD, this study did not demonstrate any appreciable difference between SGB and sham treatment on psychological or pain outcomes. Future studies should examine if differences in treatment methods or patient population could allow individuals with PTSD to benefit from SGB, but current evidence does not support widespread or indiscriminant clinical use of the procedure for PTSD.

Intravenous Cosyntropin Versus Epidural Blood Patch for Treatment of Postdural Puncture Headache.

OBJECTIVE: This study evaluated the efficacy of IV cosyntropin as an alternative to epidural blood patch (EBP) for refractory or severe post-dural puncture headache (PDPH). METHODS: Twenty-eight patients were randomized to receive EBP or intravenous cosyntropin after diagnosis with post-dural puncture headache. Efficacy was evaluated immediately after treatment and at 1 day, 3 days, and 7 days following treatment using self-reported verbal reported scores for pain and function related to their headache on a 10-point scale using two-way repeated measures analysis of variance (ANOVA) with multiple comparisons. RESULTS: Baseline information for the control and study cohorts showed no difference based on intent to treat analysis. EBP showed significant improvement over cosyntropin at day 1 (P < 0.001) for VRS pain and function scores; however, cosyntropin demonstrated similar efficacy to EBP immediately after treatment and days 3 and 7 post treatment (respectively, P = 0.459, P = 0.391 and 0.925 for pain and P = 0.189 and 0.478 for function). Treatment effects remained at day 1 after multivariate analysis (P < 0.001 and P = 0.002 for pain and function, respectively). CONCLUSIONS: It is reasonable to consider IV cosyntropin as the treatment of choice for patients in whom EBP is contraindicated or in austere environments where there is limited or no access to anesthesia trained providers. Future research should compare efficacy and cost of prophylaxis to treatment of PDPH with intravenous cosyntropin and evaluate the most effective dosing regimen, including duration, number, and strength of doses.

Treating intractable phantom limb pain with ambulatory continuous peripheral nerve blocks: a pilot study.

BACKGROUND: There is currently no reliable treatment for phantom limb pain (PLP). Chronic PLP and associated cortical abnormalities may be maintained from abnormal peripheral input, raising the possibility that a continuous peripheral nerve block (CPNB) of extended duration may permanently reorganize cortical pain mapping, thus providing lasting relief. METHODS: Three men with below-the-knee (2) or -elbow (1) amputations and intractable PLP received femoral/sciatic or infraclavicular perineural catheter(s), respectively. Subjects were randomized in a double-masked fashion to receive perineural ropivacaine (0.5%) or normal saline for over 6 days as outpatients using portable electronic infusion pumps. Four months later, subjects returned for repeated perineural catheter insertion and received an ambulatory infusion with the alternate solution ("crossover"). Subjects were followed for up to 1 year. RESULTS: By chance, all three subjects received saline during their initial infusion and reported little change in their PLP. One subject did not receive crossover treatment, but the remaining two subjects reported complete resolution of their PLP during and immediately following treatment with ropivacaine. One subject experienced no PLP recurrence through the 52-week follow-up period and the other reported mild PLP occurring once each week of just a small fraction of his original pain (pretreatment: continuous PLP rated 10/10; posttreatment: no PLP at baseline with average of one PLP episode each week rated 2/10) for 12 weeks (lost to follow-up thereafter). CONCLUSIONS: A prolonged ambulatory CPNB may be a reliable treatment for intractable PLP. The results of this pilot study suggest that a large, randomized clinical trial is warranted.

Does sensory stimulation threshold affect lumbar facet radiofrequency denervation outcomes? A prospective clinical correlational study.

BACKGROUND: Radiofrequency facet denervation is one of the most frequently performed procedures for chronic low back pain. Although sensory stimulation is generally used as a surrogate measure to denote sufficient proximity of the electrode to the nerve, no study has examined whether stimulation threshold influences outcome. METHODS: We prospectively recorded data in 61 consecutive patients undergoing lumbar facet radiofrequency denervation who experienced significant pain relief after medial branch blocks. For each nerve lesioned, multiple attempts were made to maximize sensory stimulation threshold (SST). Mean SST was calculated on the basis of the lowest stimulation perceived at 0.1-V increments for each medial branch. A positive outcome was defined as a ≥50% reduction in back pain coupled with a positive satisfaction score lasting ≥3 months. The relationship between mean SST and denervation outcomes was evaluated via a receiver's operating characteristic (ROC) curve, and stratifying outcomes on the basis of various cutoff values. RESULTS: No correlation was noted between mean SST and pain relief at rest (Pearson's r=-0.01, 95% confidence interval [CI]: -0.24 to 0.23, P=0.97), with activity (r=-0.17, 95% CI: -0.40 to 0.07, P=0.20), or a successful outcome. No optimal SST could be identified. CONCLUSIONS: There is no significant relationship between mean SST during lumbar facet radiofrequency denervation and treatment outcome, which may be due to differences in general sensory perception. Because stimulation threshold was optimized for each patient, these data cannot be interpreted to suggest that sensory testing should not be performed, or that high sensory stimulation thresholds obtained on the first attempt should be deemed acceptable.

Preamputation mirror therapy may prevent development of phantom limb pain: a case series.

We report the cases of 4 patients who performed daily mirror therapy for 2 wk before undergoing elective limb amputation. One patient experienced no phantom limb pain (PLP). Two patients experienced rare episodes of mild PLP without effect on their participation in physical therapy (PT) or their quality of life. One patient reported daily, brief episodes of moderate PLP without effect on his participation in PT or his stated quality of life. These results indicate that preoperative mirror therapy may improve postamputation PT compliance and decrease the incidence of PLP. Future prospective studies are needed to confirm the results of this case series.